Telephone-exchange.



PATENTED MAY 10, 1904.

C. A. ANDERSON.

TELEPHONE EXCHANGE.

APPLICATION FILED DEC. 5, 1901.

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APPLIUATION FILED DEG. 6, 1901.

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C. A. ANDERSUN. TELEPHONE EXCHANGE;

APPLICATION FILED DBO. a, 1901.

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UNITED STATES Patented May 10, 1904.

CLARENCE A. ANDERSON, OF SALINA, KANSAS.

TELEPHONE-EXCHANGE- SPECIFICATION forming part of Letters Patent No.759,492, dated May 10, 1904.

Application filed December 5, 1901. Serial No. 84,761. (No model.)

To all whom it may concern.-

a citizen of the United States of-America, and

a resident of Salina,county of Saline, and State of Kansas, haveinvented certain new and useful Improvements in Telephone-Exchanges,

of which the following is a specification.

My invention relates to telephone -ex-l changes, and has for its ob ectimprovement in party-line exchanges.

More particularly, it relates to-the switching mechanisms at the localtelephone-stations and to the electrical connections at the.

local stations and the central ofiice whereby particular subscribers onthe same party-line are selected from the whole number on the line andare placed in communication with each other.

In the accompanying drawings, Figure 1 is a plan of the switchingmechanisms located at the local stations.

on line 3 3 of Fig. 1. Fig. 4 is a diagram showing a central oflice andone local station. Fig. 5 is a diagram showing two additional stations,and Fig. 6 is an enlarged elevation of the switch at the central oilice.

In Fig. 1, S is a ratchet-wheel pivoted on a post S and normally heldagainst a stop S by means of the spring S. Secured to the wheel S is aninsulated contact-maker 26, and in the path of 26 are two contact-points27 and 43. The contact-point 27 is one step of the ratchet-wheel fromthe normal position of contact-maker 26; but the point 43 is a differentdistance for each switch on the partyline. For the first telephone itwould be one step from 27 and two from the normal position of 26, andfor each succeeding telephone it would be moved one step farther away.

Also secured to the wheel and in electrical connection therewith is asecond contactmaker 55, and in the path of 55 are three contact-strips54, 64, and 66, which are supported on an insulating-block J. The strips64 and 66 are on a level, so that when the contact-maker 55 touches oneit also touches the other. The strip 54 is thin and flexible and liesbetween and slightly above the strips 64 and 66. The end of the strip 54adjacent to Fig. 2 is a section on line I Fig. 3 is .an enlar ed sectlonthe normal position of 55 is bent downward, Bert known that LOLARnNon A.ANDERSON, 1

as shown at 540, and rests on the blockJ below the surface of the strips64 and 66. The block J is built up, as shown at J, at the ends of thestrips 64 and 66 on each side of the end of strip 54, so that the end ofthe latter strip rests in a groove. The contactmaker is also thin andflexible, so that when it is moved from its normal position it rides upover the part of 540 of the strip 54. At its extreme movement fromnormal position the contact-maker 55 drops oil of the strip 54 and restson the strips 64 and 66. On its return to its normal position thecontact-maker 55 passes under the flexible strip 54, and just before itreaches its normal position it raises the loose end and stops clear ofall three strips. The movement of the contact-maker 55 from its normalposition is by means of an electromagnet and the return is by means ofthe spring S.

Adjacent to the wheel S are two magnets N and I, which are oppositelypolarized.

These magnets are provided with a common armature N, pivoted at I andheldnormally in a mid-position by a spring N 011 the armature N is apawl N, adapted to engage the teeth of the wheel S to move it when themagnet N is energized. Adjacent to the pawl N is a pin N. arranged sothat when the magnet P is energized the said pawl will be lifted fromengagement with the wheel. Also on the armature N is an insulated. piece51,

adapted to come into contact with a contactpoint when the magnet P isoperated.

Located at convenient places are the rnagnets A and B, having armaturesA and B. 1

On the armature B is a holding-pawl B", adapted to engage theratchet-wheel S and to be released therefrom when the magnet B isoperated. Pivoted at E is a pawl E, held against a shoulder A on thearmature A by a spring on the post E.

Pivoted to the pawl B" is a rod B, the other end of which is guided by alug A on the armature A. The guided end of the rod B is supported closeto the shoulder A and the pawl E. When the magnet A is operated so as todraw the armature A against the contact 62, the pawl E catches on theshoulder-A and holds the armature in its retracted position. It when theparts are in this condition the magnet B be operated, the rod B willpush the pawl E OR of the shoulder A and permit the armature A to fallback away from the contact-point 62.

It will be evident that a simultaneous oper ation of the magnets B and Pwill release the ratchet-wheel S and permit it to be returned to itsnormal position by the springs, provided the said wheel had beenpreviously moved. The electrical connections for operating these magnetspass through the strips 64 and 66 and are held by the contact-maker 55during its return movement until just before reaching its normalposition, when the connections are broken by the contact-maker passingfrom the contact-strips to the raised portion J of the block J. Uponbreaking these connections the pawls B and N return to engagement withthe wheel S. To prevent this engagement occurring before the wheel isstopped by the post S the strips 64 and 66 extend as near as practicableto the normal position of the contact-maker 55, though it is notessential that this be nearer than two or three steps, or even more, ofthe ratchetwheel S. The reason for this is that although the pawls bland B instantly move toward engagement with the ratchet-wheel upon thebreaking of the circuits through the magnets P and B they cannot bemoved quickly enough to immediately catch the rapidly-returning wheelunless they are made very light and are adjusted very close to the teethof the wheel when they are in their released position. To obviate thenecessity of bringing the strips 64 and 66 very close to the normalposition of 55 and to allow. for slowness of movement when the spring Sbecomes weak, the pawls B and N and the armatures to which they areconnected are made heavier than absolutely necessary and when releasedare moved to a greater distance than absolutely necessary to cause suchrelease. The distance the holding-pawl B is removed from engagement withthe teeth of the wheel is determined by the position at which the magnetB is set when the mechanism is put together. The movement of the pawl Nis similarly determined by the positions of the magnet P and the stop50.

At the central office there is an arm 38, pivoted in the center andprovided with insulated pieces 35 and 47 at its ends. In the path of thepiece 35 are a series of contact-points 34, all of which are connectedto one pole of a battery X. In the path of piece 47 is a contact-strip48, connected to the other pole of battery X. Adjacent to contacts 34 isa strip 39, and adjacent to 48 is a strip 41, both of which are in thepath of the central section of arm 38. Strip 39 is connected with strip48, and strip 41 is connected with the contacts 34. In its normalposition the arm 38 stands in the position shown in Fig. 4 and whenmoved makes connection with the -contactpoints '34 and the strip 39. henthe opposite end of the arm 38 is pressed during its rotary movement,the connection is broken at 34 and 39 and ismade with 41 and 48. Thelength of the strips 41 and 48 is greater than the length of 39, so thatafter the arm has been moved to a position beyond which it will connectto 39 it is still in a position in which it may be pressed into contactwith 41 and 48. Also located at the central office are the usual devicesof such an ofiice, including drop D, clearingout drop 97, generator G,inductioncoil K, transmitter T, keys, and other devices which will bereadily understood by the later description. These devices are connectedby wires, as shown in the diagram, and from the central oflice thereruns a wire 10, to which are connected all of the local stations on theparty-line. One feature of the present system is that this wire and theground connection are the only connections between the several stations,central and local. The number of local stations on the party line islimited only by practical considerations of service, and each station isrepresented by a different contactpoint 34 at the central oifice. Inaddition to the switching mechanism previously described there are ateach local station the usual apparatus, including generator (1, ringerQ, receiver R, induction coil K, and contacts and connections such aswill become apparent in describing the operation.

The stations in the diagrams are marked No. 3, No. 4, and No. 5, andassuming that the subscriber at the station No. 3 wishes to talk to thesubscriber at station N o. 5 then the operation will be as follows:Either before or after removing his receiver R he will turn the crank ofhis generator Gr, when a current flows as follows: G, 8, 9,10, D,11,12,13,14, ground at central, to ground at station No. 3, 15, 16, G.This operates the drop D at the central oflice, whereupon. the operatorthere inserts the plug 98 in the jack 99, turns the arm 38 so that itcontacts strip 39 and the piece 35 contacts the first point 34, andpresses key 18. The subscriber also removes his receiver if he has notpreviously done so. Upon connection with the first contact-point acurrent flows as follows: X, 33, 34, 35, 36, 37, 13, 14, ground at thecentral oilice to ground at each one of the local stations on theparty-line 15, N, 25, 10, 24., 23, 22, 21, 38, 39, 4.0, X. This is acurrent in the proper direction through the magnets N of the severallocal stations to operate them and results in the movement of eachcontact-maker 26 to the adjacent contactpoint 27. Then beginning at thereceiver at station No. 3 the talking-circuit to the central office isas follows: E, 16, 15, ground, 14, 96, 17, 1s, 19, R, 15,20, 21, 22,23,24,10, 25,26, 27, 2s, 29, H, 30, 31, K, 32, R. The subscriber atstation No. 3 informs the operator at the central oiiice that he wishesto talk to station No. 5, whereupon she (the operator) moves the arm 38so that 35 sweeps over the entire series of contact-points 34 and stopsbeyond the last one. During this movement she presses the arm to makecontact with 41 and 48 after making contact with the contactpoints forstations N o. 3 and No. 5. In pressing the arm 38 she tilts it on itspivoting-post V, thereby raising the end 35 clear of the con tact-points34 and the strip 39 and causing the end 47 to engage the strips 41 and48. Upon releasing the pressure on arm 38 the spring V, which isattached to the lower face of the arm 38 and bears against the post V,returns the arm to the position shown in Fig. 6. At each contact with apoint 34 acurrent is sent, as previously described, for the firstcontact-point 34, the result of which is that the wheels S of eachstation are advanced step by step. When contact is made with 41 and 48,the current flows as follows: X, 33, 41, 38, 21, 22, 23, 24, 10, 25, 26,43, 44, 45, P, 15, ground, 14, 13, 37, 36, 46, 47, 48, 49, X. A branchof this current flows from 25 through N to 15; but as this is contraryto the polarization of N this branch is without effect on that magnet.The current through P closes 51 to 50, and as this occurs only at theparticular station which has its contact-maker 26 on the contact-point43 and as each station has this contact-point at a diiierent distancefrom the normal position of 26 it will be evident that this occurs atonly one station at a time. As the contact-points 43 of each station arerelated to the contact-points 34 of the central oflice, it will beevident that the pressing of the arm 38 in the manner described willoperate the magnets P only at stations No. 3 and No. 5. The closing of51 to permits a current to flow as follows: Y, 50, 51, 52, A, 53, 54,55, 45, Y. The current through A closes A to 62 and permits pawl E tohold this closed position. This occurs at stations No. 3 and No. 5 only.Immediately after stopping the arm 38 past the last contact-point 34 theoperator presses key 58 and turns the crank of her generator, when acurrent flows as follows: G at central, 56, 57, 58, 59, 60, 14, groundto ground at station N o. 5, 15, 16, Q, 61, H, 29, 28, 62, A, 9, 10, 24,23,22, 21 20,(:l. This current does not go through station No. 3,because the circuit has been broken at 61 by the removal of thereceiver, and does not go through the other stations, because themagnets A at those stations have not been operated. Immediately uponhearing his bell ring the subscriber at station N o. 5 removes hisreceiver, when the talking-circuit between No. 3 and No. 5' is asfollows: E of No. 3, 16, 15, ground, 15 of No. 5, 16, R, 32, K, 31, 30,H, 29, 2s, 62, A, 9, 10 to 9 or NO. a, A, 62, 28, 29, 30, 31, K, 32, B.When through talking, the subscriber turns his generator to send acurrent as follows: Gr, 8, 9, 10, 24, 23, 22, 21, 97, 36, 37, 13, 14,ground, 15, 16, G. This operates the clearing-out drop 97 and notifiesthe central oliice. Upon the previously-described movement of the arm 38the last contact made by 35 on 34 moved all of the contact-makers at thelocal stations to a position where they would drop oil of the end of thecontact-strips 54 and rest upon the strips 64 and 66. With thecontact-makers 55 in this position and notiiied that the subscribers arethrough talking the operator presses the arm 38 so as to make contactwith 41 and 48 and returns the said arm to its normal position. Uponmaking the contact a current flows as follows: X, 33, 41, 38, 21, 22,23, 24, 10, 63 of each station, 64, 55, 45, P, 15, ground, 14, 13, 37,36, 46, 47, 48, 49, X. This again closes 51 to 50, when a current flowsas follows: .Y, 50, 51, 52, B, 65, 66, 55, 45, Y. This releases theholding-pawl B and as the driving-pawl N had been previously released bythe operation of magnet P the switching mechanism is free to be returnedto its normal position by spring S. The operation of B also causes therod B to push the pawl E off of the shoulder A, thus permitting thearmature A to fall back away from the contact-point 62. This series ofactions occurs at each one of the local stations, because they are allin the same position and because they are all connected to ground andthe party-wire 10.

What I claim is 1. In a switching mechanism, the combination with aratchet-wheel, a magnet for moving it from its normal position, and aspring for returning it to its normal position when released, of acontact-maker secured to and movable with said ratchet-wheel, and threecontact-strips, said strips being arranged so that when contact-maker ismoved in one direction it is in electrical connection with one of saidstrips and when moved in the opposite direction it is in electricalconnection with the other two strips.

2. A contact-maker and means for moving it to and from a normalposition, contactstrips located in the path 01 said contactmaker andarranged so that when said contactmaker is moved in one direction it isin contact with one strip and when moved in the opposite direction it isin contact with a diiferent strip, a telephone-station at which saidcontact-maker is located and a wire extending to other stations,areceiver, electrical devices for connecting said receiver to anddisconnecting it from said wire, connections fromsaid contact-maker tosaid electrical devices, and means whereby said devices are operated byelectrical impulses sent through 'said contactmaker while in connectionwith said strips.

3. A series of switching mechanisms and magnets for moving them aprescribed distance from their normal positions, a receiver for eachswitching mechanism, a party-line, an electrical connection closed byeach switching mechanism at different points in the length of IIO &

their movements whereby the associated receivers may be connected to theparty-line, a second electrical connection closed by each switchingmechanism at the terminal of its movement, and devices operated byelectrical impulses sent through the last-named electrical connectionsfor causing said switching mechanisms to be returnedto their normalpositions.

4:. The combination with a series of switching mechanisms and means formoving them from their normal positions, of electricallyoperated devicesfor causing the return of said mechanisms to their normal positions,normally open contact devices connected to the devices for causingreturn movement and located at the extreme positions of the movements ofthe switching mechanisms, and means for closing said contact devices bythe movement of said mechanisms.

5. The combination with a telephone re ceiver, a party-line wire, and amagnet for connecting said receiver to said wire, of a switchingmechanism, devices for propelling it, a magnet for releasing it from itspropelling device, two contact-makers carried by said switchingmechanism one of which is arranged to close connections to theconnecting-magnet and the other of which is arranged toclose connectionsto the releasing magnet, and means for sending electrical impulsesthrough said contact-makers and their respective magnets.

Signed at Salina, Kansas, this 29th day of November, 1901.

' CLARENCE A. ANDERSON. Witnesses:

ELMO VVELCH, W. T. VVELoH.

